Tricarbon (systematically named 1λ
2,3λ
2-propadiene and ''catena''-tricarbon) is an
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the
chemical formula (also written
(μ-C)Cor ). It is a colourless gas that only persists in dilution or solution as an
adduct. It is one of the simplest
unsaturated carbenes. Tricarbon can be found in interstellar space and can be produced in the laboratory by a process called
laser ablation
Laser ablation or photoablation (also called laser blasting) is the process of removing material from a solid (or occasionally liquid) surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser ...
.
Natural occurrence
Tricarbon is a small
carbon cluster first
spectroscopically observed in the early 20th century in the tail of a comet by
William Huggins and subsequently identified in
stellar atmospheres. Small carbon clusters like tricarbon and
dicarbon
Diatomic carbon (systematically named dicarbon and 1λ2,2λ2-ethene), is a green, gaseous inorganic chemical with the chemical formula C=C (also written 2or C2). It is kinetically unstable at ambient temperature and pressure, being removed throug ...
are regarded as soot precursors and are implicated in the formation of certain industrial
diamonds and in the formation of
fullerenes.
C
3 has also been identified as a transient species in various
combustion reactions.
Properties
Chemical properties
The chemical properties of C
3 was investigated in the 1960s by Professor Emeritus
Philip S. Skell of
Pennsylvania State University
The Pennsylvania State University (Penn State or PSU) is a Public university, public Commonwealth System of Higher Education, state-related Land-grant university, land-grant research university with campuses and facilities throughout Pennsylvan ...
, who showed that certain reactions of carbon vapor indicated its generation, such as the reaction with isobutylene to produce 1,1,1',1'-tetramethyl-bis-ethanoallene.
Physical properties
The ground state
molecular geometry of tricarbon has been identified as linear via its characteristic symmetric and antisymmetric stretching and bending vibrational modes and bears
bond lengths of 129 to 130
picometer corresponding to those of
alkenes. The
ionization potential is determined experimentally at 11 to 13.5
electronvolts.
In contrast to the linear tricarbon molecule, the
cation
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
is bent.
Nomenclature
The systematic names ''1λ
2,3λ
2-propadiene'', and ''μ-carbidodicarbon'', valid
IUPAC names, are constructed according to the substitutive and additive nomenclatures, respectively.
In appropriate contexts, tricarbon can be viewed as
propadiene
Propadiene () or allene () is the organic compound with the formula . It is the simplest allene, i.e. a compound with two adjacent carbon double bonds. As a constituent of MAPP gas, it has been used as a fuel for specialized welding.
Production ...
with four hydrogen atoms removed, or as propane with eight hydrogen atoms removed; and as such, ''propadienediylidene'' or ''propanetetraylidene'', respectively, may be used as a context-specific systematic names, according to substitutive nomenclature. By default, these names pay no regard to the radicality of the tricarbon molecule. In even more specific context, these can also name the non-radical singlet state, whereas the diradical state is named ''propadienediylylidene'', or ''propanediyldiylidene'', and the tetraradical state is named ''propedienetetrayl'' or ''propanetetraylylidene''.
[Skell, P. S.; Wescott, L. D. (1963)]
See also
*
Hydrocarbons
*
Alkenes
*
List of molecules in interstellar space
*
Cyclopropatriene
Cyclopropatriene is a hypothetical compound () which is an allotrope of carbon. It was once proposed as a candidate for a spectroscopically observed tricarbon species. It is a cyclic cumulene
In organic chemistry, a cumulene is a compound hav ...
References
Further reading
*
*
{{Molecules detected in outer space
Astrochemistry
Allotropes of carbon
Homonuclear triatomic molecules